1. Field of the Invention
This invention relates generally to the field of rigid disc data storage devices, and more particularly, but not by way of limitation, to a low profile structure for a spindle motor used to rotate the discs on which data is stored.
2. Brief Description of the Prior Art
Disc drives of the type referred to as "Winchester" disc drives are well known in the industry. Such disc drives typically use one or more rigid discs coated with a magnetic medium for the storage of digital data. These discs are mounted for rotation at a constant speed on a brushless dc spindle motor whose speed is carefully controlled by digital electronics.
Demands of the market and advances in technology have lead to the reduction in the physical size of rigid disc drives from the original fourteen inch outside diameter (O.D.) discs to drives utilizing 2.5", 1.8" and 1.3" O.D. discs, with inner diameters (I.D.) of 20 mm, 12 mm, and 10 mm, respectively. As the diameter of the discs themselves has been reduced, so too has the relative height of the disc drives. Current models of 2.5" disc drives, for instance, have been introduced with overall heights of only 12.5 mm.
Such considerations have lead to the development of the present invention, which provides a spindle motor for such a low-profile disc drive.